C. H. BEST 



on the etiology of the diabetic state in man. We have suggested that 

 it will be important to determine, by actual clinical trial, the extent 

 to which the results of these animal experiments are applicable to the 

 human subject. We have not suggested that insulin should be used 

 prophylactically in children with a diabetic family history until the 

 experimental results have been carefully tested by competent clinicians. 

 We have outlined many of the obvious difRculties which stand in the 

 way of such a clinical research. There may be many more which are 

 not apparent to the experimentalist. 



The four problems discussed briefly are a few among the many 

 in this field which demand investigation. We can look forward with 

 confidence to the development of better diets for diabetics; and a 

 lead may have been supplied by the suggestion that certain fats may 

 be used as a source of energy without the production of excessive 

 amounts of the dangerous ketone bodies. The role of some of the 

 new accessory food factors in the intensity of diabetes has recently been 

 investigated and the use of small animals made diabetic by the injec- 

 tion of alloxan will surely be of great value. 



It seems assured that there will be a better control of infections 

 which in many cases constitute the main problem in the treatment of 

 diabetics. Penicillin by its gentle and effective action may well intro- 

 duce a new era of progress in relation to the control of infection in 

 diabetic cases. 



Histaminase and Histamine 



Some sixteen years ago, we suggested the term "histaminase" 

 for the enzyme system, shown to be present in various tissues, which 

 inactivates histamine. This system has been partially purified as a 

 result of the efforts of various investigators, although a great deal 

 more remains to be done in this field as well as in the delineation of 

 its physiological significance. Histaminase has been useful, in con- 

 junction with other procedures, in the identification of histamine in 

 various tissue extracts and fluids. It is present in liver, lung, kidney, 

 and the intestinal mucosa, but is absent from the gastric mucosa. 



A great deal has been learned about variations in histamine 

 content of tissues and about the liberation of histamine in anaphylactic 

 shock, whereas the physiological role of this substance is far from 



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